Here is a question I received and answered on the now-defunct website AllExperts.com:

I am not sure whether I am asking the right person or not…but you must be driver… I am driving for 6 months I don’t know whether I am driving correctly or not…,…and I am observing my driver…whenever he wants to slow down the car from high speed, he presses the brake then after brake, he pushes half-clutch…and just to stop the car he uses full clutch…while I am a driver too…I have noted that when he applies brakes, there is a feel that brakes are applied…but when I apply brakes, it is seamless…(I use full clutch then brakes)…please tell me what is right…because our car is going to workshop regularly for the last six months(once for the brakes…once he was driving and the battery went on fire…waterbody gone, and little problems everyday)…(we got driver exactly six months ago)…whether I am using the car wrongly or him…second…he uses the 3rd gear very much…even in traffic, I mean if I do this the car vibrates, so I use second gear, and use 3rd gear only to climb flyovers, etc…and I come to 2nd gear normally from 4th…if I have to slow…my driving is smooth…and his is not…but whatever…Tell me of any mistakes we do…because the driver says gears are related to speed so to slow down, we will always use the previous gear…and to speed up the next one…I am very sorry, this is a very long question…sorry for the inconvenience.

Let’s first look at the proper use of the clutch.  The clutch is a mechanical component that separates the engine from the transmission, allowing you to change gears.  While the car is moving, you should engage the clutch completely (all the way to the floor) on every shift, whether you’re upshifting or downshifting.  The only time you should use the pedal halfway is to start the car moving from a stop.

The easiest way to tell you’re in the wrong gear is to monitor the feedback the car provides.  If your car is shuddering, you’re likely in the wrong gear.  Yes, gears are related to speed, but also to engine workload.  The gear you might use to maintain 20MPH on level ground might not be the same as the gear you’d use to maintain the same speed on a hill.  Listen to the engine, and react accordingly.  If your driving is smooth, you’re probably doing it right.